U.S. patent number 4,875,172 [Application Number 07/235,710] was granted by the patent office on 1989-10-17 for locomotion-command method for mobile robots.
This patent grant is currently assigned to Glory Kogyo Kabushiki Kaisha, Yutaka Kanayama. Invention is credited to Yutaka Kanayama.
United States Patent |
4,875,172 |
Kanayama |
October 17, 1989 |
Locomotion-command method for mobile robots
Abstract
A locomotion-command method for a mobile robot of the type
having a master section and a locomotion module wherein a
travelling route is specified by a command sent from the master
section to the locomotion module and wherein travelling on a given
direction line is set as a basic motion, and a travelling route can
be arbitrarily set by sending a command which specifies changes in
the position, direction and angle of the direction line, to thereby
enable a robot to freely travel with simple commands and to realize
effective control of the robot.
Inventors: |
Kanayama; Yutaka (Nijhari,
JP) |
Assignee: |
Kanayama; Yutaka (Ibaragi,
JP)
Glory Kogyo Kabushiki Kaisha (Hyogo, JP)
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Family
ID: |
16472159 |
Appl.
No.: |
07/235,710 |
Filed: |
August 19, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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91362 |
Aug 28, 1987 |
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715002 |
Mar 22, 1985 |
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Foreign Application Priority Data
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Sep 28, 1984 [JP] |
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59-203326 |
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Current U.S.
Class: |
701/23;
901/1 |
Current CPC
Class: |
G05D
1/0255 (20130101); G05D 1/0272 (20130101) |
Current International
Class: |
G05D
1/02 (20060101); G06F 015/50 () |
Field of
Search: |
;364/513,191-193,424.01,436,444,447,449,460,461,424.02 ;318/587
;901/1 ;180/167-169 ;340/988 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Marce et al.-"An Autonomous Computer-Controlled
Vehicle"-Proceedings of the First International Conference on
Automated Guided Vehicle Systems-Jun. 1981, Stratford-Upon-Avon,
England, pp. 113-121. .
Hollis-"Newt: A Mobile, Cognitive Robot"-Oct. 15, 1983-pp.
30-45..
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Primary Examiner: Ruggiero; Joseph
Attorney, Agent or Firm: Koda and Androlia
Parent Case Text
This is a continuation of application Ser. No. 091,362, filed Aug.
28, 1987 which is a continuation of Ser. No. 715,002, filed Mar.
22, 1985, now abandoned.
Claims
What is claimed is:
1. A control method for the travel motion of a mobile robot across
an area definable by Cartesian coordinates along a traveling route
using a main control module sending out coordinate related control
commands as well as a locomotion module moving together with the
robot and responding to the control commands and self-controlling
the local direction of movement of the robot, characterized by the
steps of:
self-controlling of robot by the locomotion module such that said
robot follows a given straight line;
sending a change of course from the main control module to the
locomotion module, said change of course command comprising data
indicative of a location at which a change of course is to occur
and data indicative of an angle between the given straight line and
a new direction of travel;
executing the change of course command by the locomotion module
when the mobile robot reaches the location at which said change of
course is to occur; and
self-controlling the mobile robot by the locomotion module such
that said robot follows a straight line along said angle in said
new direction of travel.
2. A control method according to claim 1, further characterized by
the steps of only sending position and direction data of the robot
from the locomotion module to the main control module upon a
request command from the main control module.
3. A control method according to claims 1 or 2, further
characterized by the steps of classifying the control commands sent
from the main control module by the locomotion module into fast
commands to be executed immediately and into slow commands to be
temporarily stored in a buffer memory.
4. A control method according to claim 2 further characterized in
that the request command for sending position and direction date to
the main control module is received during only a part of the time
the robot is being self-controlling or is receiving control
commands from the main control module.
5. A control method according to claim 4 further characterized by
the steps of determining by the locomotion module the position and
direction data for the robot from ultrasonic distance measuring
equipment moving together with the mobile robot.
Description
BACKGROUND OF THE INVENTION
This invention relates to a method for giving a locomotion-command
system for mobile robots such as unmanned travelling vehicles.
There have been proposed various methods for making unmanned mobile
robots travel; one method comprises the steps of emitting inductive
radio waves of a predetermined frequency from an induction wire and
making a mobile robot receive the radio waves to travel along the
route formed by the induction wire. Another method uses an optical
reflective tape and a photoelectric detector instead of the
induction wire. These methods require guiding means, as the mobile
robot of this type are controlled and guided by detecting and
compensating deviation from the route of the induction wire or the
photoelectric reflective tape which is laid on a floor. When the
layout of tools and machineries and/or facilities in a plant or a
warehouse are revised, the conveyor route formed among such
facilities should be changed accordingly, which inconveniently
needs replacing the guiding means again. Further in the case of the
method using an induction wire, it takes much time and trouble in
laying and burying the wire. The method using a photoelectric
reflective tape has another disadvantage that it is prone to dust
and easily stained or damaged.
Japanese patent laid-open No. 62424/1982 discloses a travel-command
method which obviates aforementioned detriments. In the method, the
route along which a mobile object is to travel is expressed by a
sequence of points with X-Y coordinates, which are generated in a
form of digital data, with which a region is determined. The region
and an assumed position ahead in the advancing direction determine
a region to which the object is to advance. A steering signal is
generated based upon a point on a line connecting at least two
points included within the specified region and the assumed
position of the moving object ahead thereof. However, as the
advancing route is expressed with a sequence of points with
coordinates in this method, it is not possible to smoothly specify
or to control the route when the travel-lane should change from a
line 1 to another parallel line 2 as shown in FIG. 1A, or when the
object should make a U-turn and return on a same route 3 as shown
in FIG. 1B.
SUMMARY OF THE INVENTION
An object of this invention is to provide a method for giving
commands to mobile robots which enable the robot to freely travel
without laying inductive wires or photoelectric reflective tapes on
a floor.
Another object of this invention is to provide a method for giving
locomotion-commands which enable an object to freely travel along
an arbitrary route, which can easily change travelling route, and
which can easily make the object make a U-turn.
Still another object of this invention is to provide a method for
giving locomotion-commands which enable a mobile robot to travel
freely with a simple means and which is capable of controlling
communication between a master and the robot effectively.
According to this invention in one aspect thereof, for achieving
objects described above, there is provided a locomotion-command
method for a mobile robot of the type having a master and a
locomotion module where a travelling route is specified by a
command sent from the master to the locomotion module, which is
characterized in that travelling on a given directed line is to be
a basic motion, and a travelling route can be arbitrarily specified
by sending a command which changes on the position and direction of
said directed line.
According to this invention in another aspect thereof, there is
provided a locomotion-command method for a mobile robot of the type
moving while carrying out communication between a master and a
locomotion module which is characterized in that the feedback
control time during which the robot per se executes travelling
control and the command execution control time during which
commands from said master are executed and controlled are
alternately assigned for a predetermined time.
Further, according to this invention is still another aspect
thereof, there is provided a locomotion-command method for a mobile
robot of the type which moves the robot while communicating between
a master and a locomotion module, which is characterized in that
said locomotion module has a feedback control mode by which the
locomotion module control its travel by itself and a command
execution control mode by which commands from said master are
executed and controlled, the position and direction on the
travelling line of said locomotion module are specified by using
coordinate transformation as said command, the given command and
said command are analysed in the execution control mode, and the
travel of the robots controlled according to the result of said
analysis in said feedback control mode.
The nature, principle and utility of the invention will become more
apparent from the following detailed description when read in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the attached drawings:
FIGS. 1A and 1B are the views to show examples of the movement of a
robot;
FIGS. 2 and 3 are the views to explain the principle of this
invention, respectively;
FIG. 4 is a block diagram to show the relation between a master and
a locomotion module of a robot according to this invention;
FIG. 5 is a diagram to show the communication between the master
and the locomotion module;
FIG. 6 shows the appearance of an embodiment of the mobile robot
according to this invention;
FIG. 7 is a block diagram to show an embodiment of the controlling
system thereof;
FIG. 8 is a graph to show the timing of movement thereof;
FIGS. 9 through 11 are flow charts to show respective movements of
the mobile robots;
FIGS. 12A through 12H are the views to show the movement of a
mobile robot with the command of "GO", respectively; and
FIG. 13 is a view to show the state of travel of a mobile
robot.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The principle of this invention will now be described referring to
FIG. 2.
In FIG. 2, a robot R (x, y) travels on a directed travel line X in
the direction marked with an arrow. The mobile robot R is
controlled positionwise by a servo mechanism so that it would not
deviate from the line X by a large margin although it may go
slightly toward the direction of Y-axis. In other words, the robot
R is constantly servo-controlled to make the relation y=0. When one
wishes to have the robot make a U-turn or change direction, the
commanding section gives a new directed line X' and an exit point E
(e, o) which starts the transient state from the line X to the line
X' is specified as a transition point. With this command, the robot
R is controlled to travel at a given speed until it reaches the
transition point E and then to transfer to a new route X'. The
travel line X is an X-axis of the XY-coordinates with a fixed
original point O (0, 0). When x.gtoreq.e, the robot R is controlled
to enter the transient state and is transferred to a new
X'Y'-coordinate having an origin O' (0, 0) from a point on the
X'-axis. The point is herein referred to as F. The robot R has a
position (x, y) and a direction .theta. in itself until the time it
reaches the transient point E and constantly renews the current
values with an encoder. The direction .theta. is an angle formed
between the axis X and the mobile robot R. The direction is
controlled so that a target value is set at y=0 under stationary
state wherein the direction CCW is positive and posture of the
robot R is set at (x, y, .theta.). After the transient point E, the
posture of the robot R is controlled on a new coordinate X'Y' as
(x', y', .theta.').
The coordinate transformation from the XY-coordinate to
X'Y'-coordinate is described below referring to FIG. 3. It is
assumed when a command "GO" (which will be explained hereinafter)
specifies a new coordinate X'Y' to the old coordinate XY, the
posture of the robot R which was (x, y, .theta.) is (x', y',
.theta.') in a new coordinate. The relation holds between the above
two as below; ##EQU1## From the above formula (1), the following
relations are induced; ##EQU2## When the command "GO" and so on are
executed, the coordinate transformation of the formula (2) or the
transformation from (x, y, .theta.) to (x', y', .theta.') is
carried out.
FIG. 4 shows the relation between the master 10 and the others
including the locomotion module 20 of a mobile robot. A vision
module 11 provides a sensor which identifies surroundings and a
hand-and-arm module 12 provides a manipulator. FIG. 5 shows that
communication data comprising commands C and replies RP is
exchanged between the locomotion module 20 and the master 10 at a
timing described hereinafter. Commands C are transmitted from the
master 10 to the locomotion module 20 in the unit of one byte. A
separator such as a code or a symbol ";" is inserted between
commands. Commands are classified into a slow command "SC" which is
temporarily stored in a buffer memory BM and then executed
sequentially in the order of arrival and a fast command "FC" which
is immediately executed. Slow commands "SC" are temporarily stored
in a buffer memory BM and then executed in a first-in first-out
basis. Fast commands "FC" are executed immediately without being
stored in a buffer memory BM. The locomotion module 20 has two
states; a wait state and an active state. In the wait state, a
command stored in the buffer memory BM is not executed. The state
is actuated to an active state when a fast command or a "START"
command (which will be described hereinafter) is transmitted from
the master 10. The locomotion module 20 is in the waiting state
when initialized. In the active state, the locomotion module 20
executes commands stored in a buffer memory BM in the order of
arrival. Execution of each command C is completed by the time the
step reaches a transient point of a subsequent command (for
instance C1) where the execution of the command C1 starts. If there
is no command stored in a buffer memory BM during the time a
command C0 is being executed, or if the buffer memory BM is empty,
the execution of the command C0 continued indefinitely. However, it
is always possible to end the execution of the command C0 by
transmitting such commands as "GO", "STOP 0" or "ADJUST". An active
state turns into a waiting state when a command "WAIT" (described
hereinafter) is executed. This command "WAIT" is a slow command
which is accepted only during the active state. Replies RP are
classified into "POSTURE" indicating data for the posture of the
robot, "TRANSIENT" indicating that the robot has passed the
transient point E but not reached the point F of the next
coordinate, "STATIONARY" indicating the state is stationary, and
"ERROR" indicating that an exception has taken place, that is, the
state will not return to the stationary state for a long time.
An example of control algorithm is shown below for executing
commands such as "GO", "SPIN", "STOP", "ADJUST", or "STOP 0". The
velocity V and the angular velocity .omega. are servo-controlled
with a program and data stored in ROM (Read Only Memory) or RAM
(Random Access Memory) and by the CPU (Central Processing Unit) to
follow up the target values.
When a command "GO" is given to a robot specifying the target
position xd as the point to stop, the velocity is controlled at a
fixed velocity mode until it becomes a predetermined state, and
then at a reduced velocity mode until the X becomes a predetermined
value. Then, the mode is switched to a position controlling mode,
and finally to a suspension mode. In order to execute the command,
a target velocity Vr(t) is given to correspond to the current
position x(t) for speed reduction, and when the actual speed and
the position satisfy V(t).apprxeq.0, and x(t).apprxeq.xd, the
servo-loop is switched from a velocity servo-control mode to a
position servo-control mode. For advancing a robot at a given speed
until the target position xd and stopping the same thereon, the
velocity V(x) at the point x should be; ##EQU3## If it is assumed
that the reduction in velocity is Av, the coefficient k1 is
expressed as ##EQU4## When the relation expressed by the following
formula (5) is obtained during the execution of a command, the mode
goes into a velocity reduction mode, wherein .epsilon. is an
extremely small value.
In the velocity reduction mode, for command controlling, the
angular velocity .omega. is controlled by changing f(r, .theta.,
.omega.) as follows;
This control is continued in the position control mode. The control
of the velocity V is expressed as follows: ##EQU5##
wherein GO is either -Av or +Av. After controlling in the velocity
reduction mode, if ##EQU6## are satisfied, the system goes into a
position control mode. It is controlled under the position control
mode so that
When the relation below is satisfied after the positon control, it
is judged that the robot has reached and stops at the target
position xd. ##EQU7## The mode is called a stop mode.
FIG. 6 shows the configuration of a mobile robot of powered
steering system of which this invention is applied. The bottom of
the robot is provided with a pair of travelling wheels 101 and 102
having a width l therebetween while the top thereof is provided
with a ultrasonic range finder 103. A locomotion module is mounted
on a printed board and so on within a rack 104. The locomotion
module functions to analyse commands C sent from the master 10 or
drive the wheels 101 and 102 and comprises a part of the locomotion
module 20. FIG. 7 shows the structure thereof in more detail. The
locomotion module includes a micro-computer, CPU 110. The CPU 110
is connected a communication controller 111 to communicate with the
commanding section, a ROM 112 which stores programs and parameters,
and a RAM 113 which temporarily stores the data required for
controlling. The CPU 110 is connected to a controller 114L which
controls the driving of the left wheel 101 and a controller 114R
which controls the driving of the right wheel 102. The controllers
114L and 114R control the driving of the wheels 101 and 102 via
motors 115L and 115R, respectively. The wheels 101 and 102 are
connected to shaft encoders 117L and 117R, respectively. The pulse
outputs PRL and PRR from the shaft encoders 117L and 117R are given
to the controllers 114L and 114R via the CPU 110, respectively.
Brakes 116L and 116R are controlled by motors 118L and 118R which
are driven with brake controlling singals B from the CPU 110.
The CPU 110 gives the target velocities VrL and VrR to the
controllers 114L and 114R. Suppose the velocity of the robot 100 is
V and the angular velocity is .omega., then ##EQU8## Therefore, the
target velocities VL and VR are determined by the following
relation may be induced from the formula (13). ##EQU9## If the
velocity V and the angular velocity .omega. of the robot 100 are
given, the velocities VL and VR of the left and right wheels 101
and 102 are calculated according to the above formula (14) and are
given to the controllers 114L and 114R as the target velocities VrL
and VrR, respectively. The velocities VL and VR of the wheels 101
and 102 are measured by the shaft encoders 117L and 117R,
respectively. As the outputs PRL and PRR therefrom have been given
to the controllers 114L and 114R, the velocities VL and VR are
controlled to ultimately coincide with the target velocities VrL
and VrR, respectively.
The controlling method is described for a mobile robot of power
wheeled steering type in the foregoing statement, but it may be
similarly applied to those of front-wheel steering, rear-wheel
driving types and others.
FIG. 8 shows the operation timing and operation modes of the
locomotion module. The robot 100 is initialized at time t1 when the
power is on, stays in the initialization mode until a predetermined
amount of time T0 has elapsed, during which period the current
position (x, y) is set at the point (0, 0), the angle is set as
.theta.=0, and necessary control-parameters and the others are
automatically set. After the time T0 has elapsed or after the time
point t2, the feedback control mode of the time T1 and the command
execution control mode of the time T2 are at the cycle T. The
feedback control mode is assigned to execute the velocity control
and position control which have been described in relation to the
control system in FIG. 7. The command execution control mode is
assinged to analyse the content of the commands received from the
master via the communication controller 111 and to execute the
result of this analysis. Sufficient time is assigned for all those
tasks. The locomotion module sequentially repeats the feedback
control mode and the command execution control mode at the cycle of
the time T, but, when it receives a reply request signal of a
predetermined form from the master (if a necessity arises), it
immediately goes into the communication control mode so as to carry
out necessary communication task within a predetermined duration of
time. This communication method is advantageous compared to the one
to transmit the state of the locomotion module constantly to the
commanding section as the communication traffic would not be
exessive. The section is returned to the original mode after a
predetermined time has passed and kept in that mode. FIG. 8 shows a
case where a communication request signal is sent at time t3 during
the feedback control mode and another case where a communication
request signal is sent at time t4 during an execution control mode.
In both cases, the section immediately returned into the previous
modes after the end of the communication control mode. By this
arrangement, it is apparently possible to execute the travelling
operation and the communication operation of the travelling section
cocurrently.
FIG. 9 is a flow chart to show the communication between the master
and the locomotion module. The CPU 110 of the robot 100 is
constantly testing whether a command from the master is coming or
not (Step S1). If a command comes, each byte of the command is
transmitted to the CPU 110 from the master via the communication
controller 111 (Step S2), the step is repeated until the command
data has been taken completely (Step S3). The command received is
tested whether it is a fast command or not (Step S4). If it is a
fast command, it is immediately executed (Step S5). If it is not a
fast command, then it should be a slow command to be stored in a
buffer memory BM and registered (Step S6). The CPU 110 tests
whether or not the master has a request for communication (Step
S7). If there is a request, data by one byte, for example the data
indicating the current posture of the robot 100, it is sent to the
master byte by byte to complete the job (Step S8).
FIG. 10 shows a flow chart of the operation at the feedback control
mode. The CPU 110 constantly is testing whether or not there is a
data communication request from the master (Step S10), and if there
is such a request, the CPU 110 reads the pulse data PRL and PRR
from the pulse encoders 117L and 117R to get velocity data (Step
S11). The CPU 110 then tests whether the locomotion module is in an
active state or not (Step S12), and if it is in an active state,
the CPU 110 sends the control value VrL and VrR which are
calculated from the current position x(t), the target position xd,
etc. (Step S13), and renews the current position (x(t), y(t),
.theta.(t)) (Step S14). The CPU 110 further tests whether the
locomotion module is in an active state or not (Step S15), and if
it is not in an active state, the CPU 110 actuates a brake control
signal BC to apply brake (Step S16). If the locomotion module is in
an active state, the CPU110 judges whether it is a "GO" command or
not (Step S20), and if it is a "GO" command, compares the current
position x(t) with the target position xd (Step S21). If it is not
a "GO" command, or even if it is a "GO" command the target position
xd (for instance the point E) is larger than the current position
x(t), the CPU 110 tests whether it is a transient state or a
stationary state (Step S22) and tests whether the command has been
completed or not (Step S23). If the command has not been completed,
the CPU 110 continues to execute the command and if the command has
been completed, the CPU 110 executes a slow command stored in a
buffer memory BM (Step S24) and then calculates the next target
velocity (Step S25). If the CPU 110 finds the current position x(t)
at the Step S21, it is more than the target position xd, it carries
out aforementioned coordinate transformation to complete the job
(Step S26).
FIG. 11 is a flow chart to show an example of command execution
control mode. The CPU 110, whenever step comes to a command control
(Step S30), always examines the format of the command to test
whether there is an error or not (Steps S31 and S32), and if there
is an error, it recognizes the command as a command error (Step
S33). If there is not an error, the CPU 110 checks it again (Step
S34), and converts the command into the internal format suitable
for execution (Step S35), and tests whether it is a slow command or
not (Step S36). If it is a slow command, the CPU 110 stores the
command in the buffer memory BM (Step S37), and if it is not a slow
command but a fast command, the CPU 110 sub-classifies it and
executes the command (Step S40).
The types and content of the commands C will now be described
below.
A command C is classified as a slow command SC or a fast command
FC. A slow command SC is classified as a "GO" command, a "STOP"
command, "WAIT" command, a "REVERSE" command, a "VELOCITY" command,
a "CONTROL" command, a "SET BRAKE" command or a "RESET BRAKE"
command. A fast command FC is classified as a "GO 0" command, a
"START" command, a "STOP 0" command, a "ADJUST" command, a
"VELOCITY 0" command, a "GET" command, a "CANCEL" command, a "FREE
MOTOR" command or a "SERVO" command. Each command is described as
follows:
A new coordinate system X'Y' is obtained by parallel-translating
the current coordinate system XY and then rotating it by angle
.theta.. The mobile robot 100 is transferred to the new X'-axis and
the transient point E thereof is a point (e, 0) or the point where
X=e on the old coordinate system. Effects of various "GO" commands
from the locomotion module 10 on, the robot 100 is illustrated in
FIGS. 12A through 12H.
With the command "GO, 0, 0, 0;" which does include any indication
for change of direction is given, the robot 100 advances on the
travel line X (=X') as shown in FIG. 12A. The command "GO, 50, 0,
45;" specifies the coordinate system X'Y' having the origin at (50,
0) and the revolutional angle at 45.degree.. The robot therefore
transfers its course to the axis X' as shown in FIG. 12B. As the
command "GO, 0, 0, 180;" means the change of direction at the
origin (0, 0), the robot 100 travels in the opposite direction as
shown in FIG. 12C. If the robot 100 receives a "GO" command while
travelling, it will make a turn as follows. As the command "G60,
100, 0, 30;" has the origin at (100, 0) on the new coordinate
system X'Y', the inclination at 30.degree. and the transient point
E at (60, 0), the robot 100 follows the route indicated in FIG.
12D. FIG. 12E illustrates the movement of the robot 100 when the
command is for the transient point E at (50, 0) and the inclination
angle .theta. at 140.degree.. As the command "G110, 100, 0, 90;"
indicates a transfer at the position E (110, 0) past the new origin
(100, 0), the robot 100 moves as shown in FIG. 12F at the
rotational angle .theta.=90.degree.. When the command "G100, 0, 40,
0;" is received, the robot 100 will move to a new X'-axis from the
transient point E (100, 0) following the route as shown in FIG. 12G
and when a U-turn command "G100, 0, -50, 180;" is received, the
robot 100 will move as shown in FIG. 12H.
This command is effective only when the robot 100 is in a stop
state. Otherwise, the command in ignored. It makes the robot spin
by the angle .theta. and stop after execution of the command. No
coordinated transformation is carried out by this command.
This command makes the robot 100 stop at a point (s, 0) on the
X-axis. If the robot has already passed the point, it recedes to
the alone point (s, 0) and stops thereon. The command is ignored
while the robot 100 is in a stop state.
This command makes the robot 100 enter into a waiting state.
With this command, the robot 100 reverses the direction of
travelling but no change occurs on the route per se before and
after the "reverse" command.
This command changes the travelling velocity at the stationary
state to determine the velocity of "GO" and "SPIN" commands which
might appear later
This is a slow command to change control parameters by a servo-loop
in order to change the route or required time of the travel of the
robot 100 at the transient state C1 denotes the type of a parameter
and C2 its value.
This is the command to apply the brakes 116L and 116R of the robot
100.
This command releases the brakes previously applied on the robot
100.
This is the command to make the robot 100 start travelling by
changing the state from waiting to active.
This is the command to stop the robot 100 in emergency. Unlike the
"Stop" command, it does not specify any "s".
This command is similar to the aforementioned "GO" command in
transferring onto a new coordinate system. This command is used
wihle a "GO" command is being executed, in order to revise the
position of the origin or minutely modify the route. This therefore
does not specify the transient point E.
This command changes the velocity of the robot 100 while another
command is being executed.
This command requests the robot to send back data of the current
state. Responding to this command, the robot 100 sends a reply
RP.
This is the command to cancel all slow commands SC stored in a
buffer memory BM in order not to execute it.
This is the command for moving the robot 100 manually.
This is the command for moving the robot 100 with the servo
mechanism.
A command sequence shown in FIG. 13 makes the robot 100 in a stop
state at the position P1 advance to the position P2, and recede to
the position P3. With the last "START" command S, the robot 100
starts travelling.
As is described in the foregoing statements, this invention enables
to travel a robot freely with simple commands to realize thereby
effective control of the robot. As the travelling section of this
invention is separately provided, the similar advantage can be
obtained even if commands are sent by radio or similar means.
It should be understood that many modifications and adaptations of
this invention will become apparent to those skilled in the art it
is intended to encompass such obvious modifications and chages in
the scope of the claims appended hereto.
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